报告题目：Nonlinear dynamical systems and group theory approach

报告摘要：The first part of the presentation will point out some basic facts on how nonlinear dynamical systems described through differential equations can be investigated using the Lie symmetry method. The method supposes to find some coordinate transformations which leave invariant the class of solutions for a given differential equation. These symmetry transformations can be used for determining the invariants of the considered evolutionary equation and, based on that, the reduced equation with same solutions as the former one. The reduced equation has a simpler mathematical form and could be solved. Its solutions have to be solutions for the initial equation, too. So, following this approach, one can obtain particular class of solutions for the initial equation.

In the second part of the talk, the algorithm will be exemplified on two different types of equations:

(i) the Yang-Mills mechanical model - a system of ordinary differential equations with polynomial nonlinearities:

(ii) the Ricci flow model - a second order partial derivative equation in 2+1 dimensions coming from cosmology:

报告人：Radu Constantinescu

时 间：2016年5月25日(星期三) 13:30-14:30

地 点：3-N113 A

人物名片： Radu Constantinescu

Professor, University of Craiova, Romania

Fields of scientific interest: Nonlinear dynamical systems, constrained dynamics.

Publishing activity: more than 100 papers in ISI or other journals indexed in International Databases, 14 invited lectures in International conferences, 23 papers published in Romanian journals, author and co-author of 6 books.

Participation in research contracts (national and international): 14 as director and 9 as member of the research team.

Membershipof professional bodies/ international recognition: member of IEEE, Mathematical Society (USA) and Romania Physical Society (RPS). Counsellor of European Union for Higher Education and promoters of Bologna Process for Romania. President of SEENET – MTP (SouthEastern European Network for Mathematical and Theoretical Physics), General secretary of RPS. Reviewer for Mathematical Reviews (USA), Central Eur. Journal of Physics and for other journals.